The present invention relates to a method of winding a high speed running yarn onto bobbins serially presented to a winding position, and without yarn stoppage or loss of yarn between bobbin changes. The method is particularly applicable to the production of man-made fibers produced in a spinning installation.
U.S. Pat. No. 4,431,138 discloses a method and apparatus for serially winding a high speed running yarn onto bobbins and wherein two bobbin receiving spindles are mounted on a rotatable turret which is adapted to serially deliver the bobbins to the winding position. When the first bobbin becomes full, the turret is rotated to move the full bobbin laterally away from the yarn traverse guide, and the spindle with an empty bobbin and an associated yarn catching notch is moved into the yarn path of travel while being rotated, and with the notch being positioned axially outside the yarn traverse stroke. The separated full bobbin, which continues to receive the yarn, is then moved axially so that an end portion is aligned with the plane of the yarn catching notch on the empty bobbin. An auxiliary yarn guide is then moved to engage the yarn and terminate its traverse, and the guide then moves the yarn into the plane of the yarn catching notch, and so that the yarn is initially wound on the axially extended end portion of the full bobbin until the notch catches the Yarn, at which point the yarn breaks and commences to be wound upon the rotating empty bobbin. The auxiliary yarn guide then releases the yarn so that it is caught and again traversed by the traverse guide. Similar doffing methods are disclosed in DE-PS No. 24 61 223, and in PCT application No. DE 89-00094.
In the above described yarn winding methods, the empty bobbin carries a yarn catching notch or groove which is arranged in one normal plane of the bobbin. For catching the yarn in the groove or notch, the yarn has to be guided in this normal plane. It is, therefore, necessary to stop traversing of the yarn and to lead the yarn into the normal plane. As a result, the yarn length between the rotating empty bobbin and the preceding delivery system develops slack, which often leads to the formation of a lap of the yarn on the delivery system.
In the above described winding methods, the yarn tension between the rotating empty bobbin and the preceding delivery system is further decreased, when the yarn is caught in the groove of the empty bobbin, since the empty bobbin is rotated in a direction, so that its surface travels opposite to the direction of the yarn movement. However, the above problem of lap formation due to yarn slackening during the yarn transfer operation is also found in other types of yarn winding apparatus, in which the turret is rotated in such a way that the empty bobbin is rotated in a direction so that its surface travels in the direction of the yarn movement.
It is accordingly an object of the present invention to provide a method of serially winding yarn packages, and wherein the tendency of the yarn to slacken during the yarn transfer operation is eliminated or at least reduced, to thereby reduce the risk of a breakdown in the operation by reason of a lap formation on the delivery system.